Which of the following observations helps to determine whether a chemical reaction has taken place or not?

(i) Change in state.

(ii) Change in colour.

(iii) Change in shape

(iv) Evolution of gas.

(v) Change in temperature.

(ii), (iii), (iv), (v)

No worries! We‘ve got your back. Try BYJU‘S free classes today!

(i), (ii), (iv), (v)

Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses

(i), (ii), (iii), (v)

No worries! We‘ve got your back. Try BYJU‘S free classes today!

(iii), (v)

No worries! We‘ve got your back. Try BYJU‘S free classes today!

Open in App

Solution

The correct option is D.

(i), (ii), (iv), (v)
The observations that help us for determining a chemical reaction are:

(a) Change in state ( Electrolysis of water in a liquid state gives off oxygen and hydrogen gases )

(b) Change in colour ( When sugar is heated it turns brown )

(c) Evolution of gas ( Ferric sulphate on heating gives ferric oxide and sulphur dioxide and sulphur trioxide gases are evolved).

(d) Change in temperature ( When water is added to quick lime, temperature of the mixture increases )

# change in shape is a physical reaction (ex: cutting of wood )

Suggest Corrections

Similar questions

While teaching the topic of physical and chemical changes, Mahima’s teacher listed the conditions that take place during a change.

I. Change in state

II. Change in colour

III. Evolution of a gas

IV. Change in temperature

He then asked Mahima to identify the conditions based on which it can be said with certainty that a particular change is chemical in nature.

Among the changes that are listed by the teacher, which changes should be selected by Mahima?

Give 1 example which illustrates the following characteristics of a chemical reaction

(I) evolution of gas

(II) change of colour

Question 3

A chemical change may involve
(a) change in colour only
(b) change in temperature only
(c) evolution of gas only
(d) All of the these

Join BYJU'S Learning Program